1. Field of the Invention
The present invention relates to an insulator for a wheel suspension system of a vehicle wherein the vehicle includes a mounting base and a striking base with the mounting and striking bases moveable relative to each other along an arced line of motion.
2. Description of the Related Art
Insulators for absorbing loads and dampening vibrations in vehicles are known in the prior art. Such insulators include jounce bumpers for disposition in wheel suspension systems.
The wheel suspension system includes a mounting base and a striking base spaced from and moveable relative to the mounting base. The insulator includes a shoulder portion and an impact portion and the shoulder portion presents a mounting surface for coupling to the mounting base. The impact portion is coupled to the shoulder portion for compression between the mounting base and the striking base when the striking base contacts the impact portion during movement of the mounting base relative to the striking base.
Insulators of these types are formed from elastomeric materials such as rubber or microcellular polyurethane such that the insulator compresses and absorbs loads between the mounting base and the striking base. When the insulator formed of elastomeric material is subjected to compressive forces, the insulator collapses. When the compressive forces are removed from the insulator, the insulator returns to the original shape and thereby regains its form.
Prior art insulators formed of elastomeric materials are designed for linear motion and compression, i.e., the mounting base and the striking base move toward and away from each other along a straight line. In such a configuration, the insulator travels along a straight line and includes a contact surface that is parallel with the striking base so that the insulator collapses linearly and compresses uniformly.
Some wheel suspension systems are arranged such that the mounting base and the striking base move relative to each other in an arced line of motion. In such a system, the insulator is compressed in the arced line of motion. In a twist axle suspension system, i.e., a live axle, the insulator is compressed in the arced line of motion. Other examples wherein the insulator is compressed in the arced line of motion includes when the insulator is mounted to a control arm or to a leaf spring. Insulators of the prior art can lack durability when subject to such compression along the arced line of motion. When moving along the arced line of motion, the insulator contacts the striker surface angularly. As such, upon contact with the striker surface, a portion of the insulator disposed on the interior of the arced line of motion is in compression and a portion of the insulator disposed on the exterior of the arced line of motion is in tension. The compression of the portion disposed on the interior of the arced line of motion is nonuniform, i.e., compression varies across the portion, and such nonuniform compression causes the portion on the interior of the arced line of motion to bulge. Additionally, tension in the portion of the insulator on the exterior of the arced line of motion is destructive to the elastomeric material by causing the elastomeric material to crack or tear.
Accordingly, it would be desirable to manufacture an insulator formed of elastomeric material that is configured to be more durable and reliable than insulators contemplated in the prior art when mounted in a wheel suspension system including a mounting base and a striking base that move relative to each other in an arced line of motion. Specifically, it would be desirable to manufacture an insulator that is designed to reduce or eliminate nonuniform compression and tension in the insulator.